1. Field of the Invention
The present invention relates to an image recorder recording an image with a plurality of light beams.
2. Description of the Background Art
A light emitting diode (LED) array or a laser array capable of emitting a plurality of light beams is employed as a light source applied to such an image recorder. The light beams emitted from the light emitting diode array or the laser array can be modulated independently of each other.
There has been proposed an image recorder employing a bar laser (broad area semiconductor laser) linearly formed with a number of emitters as a light source and a spatial light modulator for dividing a light beam emitted from the bar laser into a plurality of light beams and modulating the plurality of light beams independently of each other.
While a light emitting diode array having a relatively large number of elements can be implemented, the brightness (power) of each element is so low that the light emitting diode array can be applied only to a recording material having high sensitivity. While a laser array capable of emitting a laser beam of a relatively high output from each element has been developed, the total output of the laser array is insufficient due to a relatively small number of elements such that an image cannot be recorded on a low-sensitive recording medium of a thermal material or the like at a sufficient speed with the laser array, since image-recording on the thermal material is attained by converting the energy of a light beam to heat, for example.
On the other hand, a bar laser having a high output has been developed and hence an image can be recorded also on a recording medium having relatively low sensitivity when the bar laser is employed along with a spatial light modulator. When a light beam emitted from the bar laser is divided into a number of light beams by the number of elements of the spatial light modulator, however, the power of the light beam per element, i.e., the power for recording an image of a single pixel is disadvantageously reduced.
Thus, the image cannot be recorded on the recording medium having low sensitivity at a high speed even if the bar laser is used. When a thermal material is employed as a recording material, sensitivity is reduced to cause reciprocity law failure if the light beam has low illuminance. In this case, the image cannot be properly recorded on the recording medium even if the image recording speed is reduced.